This is the set of two chilled cocktail glasses that keeps whiskey cold without leaving unsightly rings on furniture. Simply freezing the glass for four hours activates the thermal liquid within its double walls, turning the crystal-clear glass frosty white. The glass quickly chills a beverage and keeps it cold for up to an hour without diluting it as melting ice does. The removable natural cork sleeve serves as a built-in coaster that prevents rings from forming on tabletops, and provides a comfortable, insulated grip for your hand. Can also be used to chill iced tea, lemonade, and soft drinks. Made from shatter-resistant borosilicate, the mouth-blown 4 1/2 oz. glass is dishwasher safe; cork sleeve washes by hand. Set of two. Each glass 4" H x 3 1/4" diam. (10 oz.)